3M™ Advanced Systems Tester 900AST Series
To change the coaxial configuration go to the TDR function and press the Setup key.
Use the and keys and the Blue numeric keys to enter the length of cable to analyze. Enter a length longer than the cable being tested but as close as possible to the total length of the cable.
When the correct information is displayed on the
Auto TDR screen, press the key to start the analysis. The 900AST performs tests to determine if the cable is shorted, open circuited, or has a resistance fault.
Note: Auto TDR operates from a captured trace. The trace is not ‘live’ as in the standard TDR mode.
Auto TDR Resistive Faults
Note: Resistance faults are very difficult to detect using TDR techniques. If a resistance fault is detected, the 900AST tester prompts you to consider using the RFL (Resistance Fault Locate) function as shown below.
Auto TDR Trace Analysis
If the Auto TDR detects an open circuit, the cursor is positioned at the location of the open circuit and OPEN is displayed below the trace. If the Auto TDR detects a short circuit or low resistance fault, the cursor is positioned at the location of the short circuit and SHORT is displayed below the trace.
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